Preheat the oven to 275°F. Grease and flour two round 9-by-2-inch cake pans. (See Kelly's Notes.)

In a small bowl, combine the mashed bananas with the lemon juice and set aside.

In a separate bowl, whisk together the flour, baking soda and salt. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and the sugar until light and fluffy, then beat in the eggs one at a time.

Add the vanilla and then beat in the flour mixture alternately with the buttermilk.

Fold in the mashed banana mixture and divide the batter evenly between the prepared cake pans. (See Kelly's Notes.)

Bake the cakes for 55 to 60 minutes until a toothpick inserted comes out clean.

Remove the cakes from the oven, place them on baking sheets and immediately transfer them to the freezer for 45 minutes to cool while you make the frosting.

In the bowl of a stand mixer fitted with the paddle attachment, beat the cream cheese until smooth. Add the butter and beat until smooth, scraping down the sides as needed. Sift the confectioners’ sugar into the bowl, then add the vanilla extract and beat until light and fluffy, about 2 minutes.

Remove the cakes from the freezer and transfer one cake onto your serving platter. Top the cake with half of the cream cheese frosting. Place the second cake on top and frost it with the remaining cream cheese frosting. Sprinkle the top of the cake with the chopped walnuts (optional). Slice and serve.

The secret tip that makes this recipe the best-ever banana cake is that the cake bakes up low and slow at 275°F for about 1 hour. It will be less moist if you try to rush the cooking time and avoid placing it in the freezer straight from the oven. The blast of cool air helps seal in the moisture.

It's important to note that the round cake pans are 9 inches wide by 2 inches tall. The amount of batter in this recipe will not fit in round cake pans that are only 1 inch tall.

This recipe will also work with a 9-by-13-by-2-inch cake pan. The baking time will vary, so it's important to test the cake with a toothpick after it's baked for about 50 minutes.